Conventionally, in order to observe blood or the like by a microscope or similar apparatus, a smear preparing apparatus in which blood or the like is dropped on a glass slide and smeared by a spreader glass (smearing member) to generate a smear is used.
Since each sample has different characteristics such as particle density, viscosity and the like, if the smear is always generated under the same condition, the smear is unsuitable for observation in some samples.
Therefore, there is known a smear preparing apparatus in which the smearing conditions are established for each sample based on a measurement result from a blood analyzer (refer to U.S. Pat. No. 5,209,903).
According to such a conventional apparatus, the smearing condition is determined based, for example, on a hematocrit value. In addition, since it is known that blood viscosity generally increases as the amount of hemoglobin increases, it is possible to establish the smearing condition based on the measurement result of the hemoglobin amount.
In addition, although the method of setting the smearing condition by the above-described conventional apparatus is very effective when the smear is automatically generated, it does not address the case of special samples or various kinds of user's needs.
For example, although the hematocrit value of a leukemia patient is normal or relatively small, it has been found that the WBC (White Blood Cell) of the leukemia patient is weak and liable to be destroyed.
When a blood smear of such a patient is made, it is necessary to make it thicker than the smear made under smearing conditions based on the normal hematocrit value when the blood on the slide glass is smeared by the spreader glass, so as not to destroy the WBC.
In addition, observers who observe the smear by a microscope have different demands for the smear. That is, some observers want to observe a widely spread smear having a small thickness, while some observers want to observe the smear thickly collected in a small region.